Gas, not planets, may be source of rings around stars

Interactions within dust disks may form elliptical patterns

Rings around distant stars aren’t necessarily a sign of orbiting planets. That’s the conclusion of a simulation that challenges a tantalizing notion in planetary science: that elliptical voids in a star’s dusty debris disk betray a planet’s presence. Instead, the rings could result from interactions between the dust and gas.

“People claim too often that the rings we see are due to planets,” says planetary astrophysicist Wladimir Lyra of Caltech.

As young star systems evolve, the surrounding gas dissipates and dust particles collide and clump together. The hardiest of those blobs carve out ring-shaped pathways in the star litter and, astronomers think, form planets. While distant planets are difficult to image directly, those rings have been found circling several stars (SN Online: 6/19/13).

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